Antimicrobial resistance (AMR) is a present, pressing global public health crisis associated with rising morbidity and mortality rates due to previously curable infectious disease. Targeted drug delivery is an important approach to address AMR due to its ability to improve the therapeutic performance of antibiotics without leading to any adverse effects or organ toxicities. In this review we explore molecular mechanisms of AMR and drawbacks of conventional antibiotic therapies and discuss unique drug delivery approaches to compensate these. Nanoparticulate carrier systems, stimuli-responsive systems, antibody–drug conjugates, and CRISPR-Cas systems are some of the carrier method designs that are promising for tackling hard to treat infections related to pathogenic strains and biofilms due to their features. Many of these are among the most significant advances in the field. However, there are many challenges to be overcome, with biological limitations, scaling and regulatory challenges, etc., before they can be employed in commercial applications. Materials are being developed, and an approach standardized and applicable to future work is in development to improve the efficiency of targeted delivery systems. Controlled drug delivery, which could be the answer to an increasing AMR problem, will not only help in alerting awareness among individuals but will also help in prolonging the activity of antibiotics by providing synergistic interdisciplinary solutions. This review emphasizes the complementary role of targeted drug delivery in transitioning from laboratory investigations to clinical therapy. It addresses underrepresented aspects, including new materials, scalability, regulatory considerations, and ethical implications, while offering a roadmap for translating innovations into next-generation antimicrobials.

Background Vitamin D deficiency is linked to cardiovascular and respiratory instability, particularly during hypoxic stress, such as in obstructive sleep apnea (OSA). However, the mechanisms connecting vitamin D status to hemodynamic and cardiorespiratory responses in hypoxia remain unclear. Objective This study aimed to assess the impact of vitamin D deficiency on hemodynamic (mean arterial pressure and heart rate) and cardiorespiratory (respiratory rate and peripheral oxygen saturation) stability in an OSA experimental model, along with the effects of dose-dependent vitamin D supplementation. Methods Fifty-six adult male Sprague Dawley rats were divided into seven groups: control, vitamin D-deficient, vitamin D-deficient with severe intermittent hypoxia (IH) and supplementation subgroups exposed to varying levels of IH. Vitamin D deficiency was induced through a diet lacking vitamin D for three weeks, followed by oral supplementation at two doses (25 µg/kg/day and 37.5 µg/kg/day) for two weeks. Intermittent hypoxia was simulated for 14 days, and serum 25-hydroxyvitamin D (25OHD) levels were measured using Elisa. Hemodynamic and cardiorespiratory parameters were recorded, and heart, aorta tissue were analyzed. Results Vitamin D-deficient groups exhibited significantly lower serum 25OHD levels and showed increased mean arterial pressure, heart and respiratory rates, and reduced oxygen saturation under hypoxia. High-dose supplementation improved 25OHD levels and improved physiological measures, particularly in moderate hypoxia subgroups (p = 0.001). Conclusion Vitamin D deficiency combined with intermittent hypoxia increased mean arterial pressure, heart rate, and respiratory rate, reduced oxygen saturation, and worsened cardiovascular histology. Vitamin D supplementation improved these changes, especially at higher dose, and protected cardiovascular structures. Graphical Abstract Vitamin D deficiency combined with intermittent hypoxia induces hemodynamic and respiratory instability and causes cardiovascular tissue alterations. Vitamin D supplementation improves physiological parameters, with greater effects at higher dose, and preserves heart and aortic structure in an obstructive sleep apnea rat model.

Haemaphysalis is the second largest genus of hard ticks (Acari: Ixodidae), both in terms of diversity and global distribution. Despite their wide occurrence, genetic information on this genus remains scarce. This study investigated the genetic diversity, phylogenetic relationships, and associated pathogens of Haemaphysalis ticks infesting small ruminants across northern Pakistan. A total of 613 ticks were collected from 95 infested goats and sheep. Four species were identified based on morphological and molecular analyses, including Haemaphysalis (Ha.) cornupunctata, Ha. danieli, Ha. montgomeryi, and a distinct Haemaphysalis sp. closely related to Ha. sulcata. Species identification was confirmed using mitochondrial 16 S rDNA and cox1 markers. Molecular confirmation of unidentified Haemaphysalis sp. was detected across multiple districts of northern Khyber Pakhtunkhwa, indicating close relation to Ha. sulcata. Pathogen screening revealed Rickettsia hoogstraalii (gltA and ompB) in Haemaphysalis sp. and Ha. danieli, Theileria sinensis-like (18 S rDNA) in Ha. montgomeryi and Ha. danieli, and Anaplasma bovis (16 S rDNA) in Ha. cornupunctata and Ha. montgomeryi. This study provides the first molecular evidence of T. sinensis-like in Ha. montgomeryi and Ha. danieli, R. hoogstraalii in Ha. danieli and Haemaphysalis sp., and A. bovis in Ha. cornupunctata and Ha. montgomeryi from Pakistan. Phylogenetic analyses supported species-level relationships and revealed substantial genetic divergence within Haemaphysalis. These findings highlight the importance of locality-based molecular surveillance for resolving cryptic diversity and improving understanding of tick–pathogen associations in mountainous regions of Pakistan.

Background: Surfactant Protein D (SP-D) is a critical immunomodulatory collectin maintaining alveolar homeostasis. Obstructive sleep apnea (OSA)-related intermittent hypoxia (IH) disrupts pulmonary surfactant integrity; however, severity-dependent SP-D dynamics remain incompletely characterized. This study explores SP-D as a potential indicator of IH-induced alveolar stress and evaluates whether Galectin-3 (Gal-3) inhibition modulates surfactant homeostasis. Methods: Forty adult male Sprague-Dawley rats (8 per group) were randomized to Control (normoxia), Moderate IH (MIH; 15–30 events/hour), Severe IH (SIH; 30–60 events/hour), MIH + Gal-3 inhibitor (Modified Citrus Pectin, 800 mg/kg/day), or SIH + Gal-3 inhibitor. IH exposure lasted 8 h/day for 10 days. Outcomes included circulating SP-D, Surfactant Protein B (SP-B), inflammatory markers, physiological parameters, and histopathological lung injury scores assessed via American Thoracic Society guidelines. Results: SP-D levels showed numerical reductions with increasing IH severity (Control: 1969.07 pg/mL [IQR: 262.15]; SIH: 1404.30 pg/mL [IQR: 351.88]), representing a 28.6% decrease. However, between-group variability resulted in non-significant omnibus testing (Kruskal–Wallis p = 0.187). Gal-3 inhibition elevated SP-D levels, particularly in severe IH (2133.95 pg/mL [IQR: 1240.70]), though high inter-individual variability was observed (CV = 58.1%). SP-B showed significant suppression under moderate IH (p = 0.019) with restoration by treatment. Exploratory correlation analysis revealed moderate positive associations between SP-D and heart rate (r = 0.587) and respiratory rate (r = 0.419) in severe IH, though these did not reach statistical significance (p = 0.126 and p = 0.301, respectively). Histologically, severe IH induced diffuse alveolar damage (total lung score: 19.67 ± 0.82). Gal-3 inhibition produced context-dependent effects: protective in severe IH but paradoxically exacerbating inflammation under moderate IH (29.20 ± 4.64 vs. 20.00 ± 4.34; p < 0.05). Gal-3 inhibition significantly attenuated cardiac injury (injury score: 0.00 ± 0.00 vs. 7.17 ± 0.75 in severe IH; p < 0.001, η² = 0.859). Conclusions: SP-D demonstrates severity-associated alterations consistent with alveolar epithelial stress during IH, though high variability limits definitive biomarker validation in this sample. Gal-3 inhibition modulates surfactant homeostasis and attenuates cardiopulmonary injury in a context-dependent manner. These findings support further investigation into SP-D as a component of multimodal severity stratification in OSA and highlight Gal-3 inhibition as a context-dependent anti-inflammatory strategy, pending validation in larger cohorts with tissue-level confirmation.

Fleas are holometabolous, blood-feeding ectoparasites capable of transmitting diverse pathogens of significant veterinary and public health concerns. Their occurrence and abundance within a given habitat depend on environmental factors and the availability of suitable hosts. In Pakistan, research on flea fauna and their associated pathogens has been neglected. To date, no reports have documented the molecular characterization of Ctenocephalides felis felis and their associated bacteria in Pakistan. In the present study, three hundred and eighty morphologically identified C. felis felis specimens-comprising 184 collected from free roaming (stray) dogs (n = 69) and 196 from cats (n = 86), were subjected to DNA extraction followed by amplification of the cytochrome oxidase subunit 1 gene (cox1) and citrate synthase gene (gltA) for flea identity confirmation and screening for the presence of associated bacteria, respectively. Amplicons of appropriate base pair sizes were sequenced and submitted to BLASTn and subsequently subjected to phylogenetic analyses. The obtained cox1 sequence from the morphologically identified C. felis felis in this study showed 100% identity and phylogenetically clustered with C. felis felis sequences from India, Australia, Thailand, China, and Laos in GenBank. Similarly, gltA sequences showed 100% identity with the Wolbachia endosymbiont of C. felis reported from the United Kingdom. This study provides the first genetic characterization of C. felis felis infesting dogs and cats, and their associated Wolbachia endosymbiont in Khyber Pakhtunkhwa (KP), Pakistan. These findings provide baseline molecular data and highlight the need for systematic surveillance and management measures to mitigate any potential veterinary and public health threats.

Ticks are significant vectors of zoonotic pathogens and harbor diverse microbial communities. The ecological origin of unusual bacteria, whether derived from the host, environment, human-associated sources, or tick-associated microbiota, remains uncertain. This study aimed to phylogenetically characterize unusual bacteria present in ticks infesting cattle, goats, sheep, dogs, domestic fowls, and bats in Khyber Pakhtunkhwa (KP), Pakistan. Tick specimens were collected, morphologically identified, and subjected to genomic DNA isolation for bacterial screening using the groEL sequence. The obtained groEL sequences were analyzed using BLAST, phylogenetic analysis, and evolutionary distance estimation. A total of 726 ticks belonging to nine species were identified. Based on BLAST results, thirteen distinct taxa of unusual bacteria were detected, namely Acinetobacter pseudolwoffii, Aggregatibacter sp., Burkholderia contaminans, Enterobacter sp., Enterobacter bugandensis, Enterobacter hormaechei, Enterobacter ludwigii, Klebsiella sp., Neisseria sp., Pantoea agglomerans, Providencia manganoxydans, and two distinct isolates of Psychrobacter sp. (MO1 and MO17). These bacteria showed low genetic distance and clustered with the corresponding high-identity sequences. This study provides the first phylogenetic insights into the unusual bacterial species in ticks from KP, Pakistan. Their detection highlights the need for further studies to determine their epidemiological significance and implications for animals and public health.